When a firearm is discharged, the forward momentum of the projectile (e.g., a bullet) and the expanding combustion gasses cause an equal and opposite force on the firearm body. The resultant backward momentum of the firearm is commonly referred to as recoil (also known as kickback, knockback, or “kick”). The rear plate (i.e., the butt) of the gun exerts a force opposite to the firing direction in the direction of the shooter. When a shoulder firearm, such as a rifle or a shotgun, is discharged, there can be a sudden and violent recoil into the shoulder of the shooter. Reducing the recoil force exerted the shooter is desirable both to protect the shooter from a possible injury and also to allow for improved accuracy because recoil can cause a shooter to flinch when firing, in anticipation of the recoil.
Several complications can arise when designing a recoil absorber. The ultimate purpose of any recoil absorber is to maintain accuracy of the firearm, but also reduce the recoil force exerted on the shooter. A non-moving pad can be added or originally manufactured on the butt of a firearm as a recoil absorber to dampen the recoil force. The pads are typically formed out of an elastomeric material. But these pads do not self-compensate for the amount of recoil force felt and do not significantly change the peak recoil force felt by the shooter.
Recoil absorbers utilizing mechanical, pneumatic, and/or hydraulic technologies are often specifically designed for one particular type of firearm. The interchangeability of these recoil absorbers between different weapons may be thus limited or impossible. One disclosure that addresses this issue is found in U.S. Pat. No. 9,133,902. The energy absorption device disclosed in U.S. Pat. No. 9,133,902 is adjustable, so that a user can turn an adjustment knob based on sizing calculations to adjust the performance of the shock absorber. However, this design requires that a user performs shock absorbing calculations and then to fine-tune the adjustment knob to allow the damping profile to match the recoil profile of the firearm. A self-compensating system thus is desired that does not require the user to operate the adjustment knob for each firearm.